The conventional calibration operation involves the following steps (1)-(5) as described in Japanese Patent Laid-Open No. 148173/1987:
(1) A calibrating jig mounted to a robot is attached to the flange at the front end of the wrist of the robot. PA1 (2) A stationary calibrating jig is placed in position. PA1 (3) The robot is moved close to a fixed position at which the calibration can be made. PA1 (4) The robot is moved slightly so that all the readings of the measuring instruments mounted to the stationary calibrating jig indicate 0. PA1 (5) The position at which all the readings of the six measuring instruments indicate 0 is registered as a predetermined position and posture of the robot.
In the conventional method, the step (4) described above has the disadvantage of being both very difficult to perform and time-consuming, because the operator moves the robot in a stepwise fashion, using a teaching box.
Accordingly, the present invention is intended to provide a quick method of calibrating a robot.
Japanese Patent Laid-Open No. 245108/1989 discloses a technique for calibrating the operation position of a positioning robot relative to an apparatus. In this technique, a measuring robot independent of a working robot is used, and only the position of the front end of a tool is controlled and calibrated. The calibration of the positional relations among the various axes of the robot at which the present invention is directed is not performed by this technique.